Remote control system



May 21, 1940. B. -w. JONES REMOTE CONTROL SYSTEM v Filed May 10, 1,934

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s 6 :w WOIJ tW mm mm m 8 B 8 .8 tag Attornqg- Patented, May 21, 1940'nEMo'rE CONTROL SYSTEM Benjamin W. Jones, Schenectady, N. Y., assignorto General Electric Company, a corporation of New York Application May10, 1934, Serial No. 724,843

a Claims.- (01. 171 -312 My invention relates to remote control systems.It is an object of my invention to provide means responsive topredetermined closing and opening operations of a load circuit forcontrolling the source of supply to which said load circuit isconnected.

It is a further object of my invention to provide a power system inwhich a characteristic of the generator may bealtered by momentarilyclosing the load circuit a predetermined number of times.

It is a further object of my invention gradually to vary acharacteristic of a generator in a system such as described abovethrough the agency of interconnected time element relays, the timedifferential of the operation 01 two of said relays determining" thelength of time the voltage varying means is energized.

Further objects of my invention will become apparent from aconsideration or the following prises. a generator I6, a driving motorII niechanically connected thereto and a load circuit I2, I3electrically connected thereto. The load circuit is employed torconnecting a load device to the generator, and in the particulararrangement illustrated the load comprises a welding are which may beestablished between an electrode l4 and the work I6.

The loari circuit l2, I3 forms the secondary of a transformer l6 whoseprimary I1 is connected to one phase '01 a polyphase source I6 throughconductors l3 and 20, the operating coil 2| of a relay 22 and aconductor23. The,motor II is connected through conductors 24, a switch26 and conductors 26 to the source of supply I8. The switch-25 is anelectromagnetic switch having, an operating winding 21 which isconnected across one phase of ,the source I6 when a starting switch 28or contacts 29 of relay 22 are closed. -The closure of contacts 23completes the following circuits from one conductor of the source otsupply'glt, through conductor '33, con-' 'ta'cts of stop switch 3|,conductors 32 and 33, contacts 29 of relay 22, conductors 34 and 36,contacts 36 of relay 31, conductor 36, operating coil 21 of switch 25and one of conductors 26 to another conductor of the source of supplyIII.

The starting switch 28 is in shunt to the contacts 26 of relay 22 andits closure will also energiae follows:

tors 32 and 33, contacts 40, conductor 35, conthe operating 001121 ofswitch 26 through a circuit comprising conductor 30, switches 31 and 28,conductors 33, 34 and 35, contacts 36 of relay 31, conductor 38,operating coil 21 of switch 26 and one of the-conductors 26. The closureof switch 25 closes its holding contacts 40 which completes a holdingcircuit tor the switch 26 as from one terminal of the source I6 throughconductor 30, stop switch 3|, conductacts 36 of relay 31, conductor 33,operating coil 21 of switch 25, and one, of the conductors 26 to.another terminal of the source of supply I8.

The operating coil 4| of relay 31 is connected across the source ofsupply 42, 43 through the following circuit: from conductor 42, throughconductor 44, the upper contacts 45 of relay 46, conductors 41 and 46 tothe other terminal 43 of the source of supply. Relay 31 is of the timedelay type and, in the particular form illustrated,

comprises a dash-pot 49 one element of which is positively connected tothe movable contact 36 which is yieldingly connected through a spring 50to the movable element of the relay 31. Thus, when the relay 31 isenergized the contacts 36 move slowly relatively to one another underthe controlling influence of the dash-pot 43, and after a'predeterminedlapse of time the contacts \36 open thereby deenergizing the operatingcoil 21 of switch 25 by means of which motor II is connected to thesource of supply I8.

two positions one of which corresponds to open circuit normal voltageconditions on the load circuit, in which contacts 46 areclosed, and theother of which corresponds to closed circuit or operating conditions onthe load circuit, in which contacts 52 are closed. Thus, when theelectrode I4 does not make an actual engagement or an arcing engagementwith the work I5, e

relay 46 completes a circuit. through contac 45, and when the electrodeis touched to the work I5 6:- a welding arc is established therebetween,the relay 46 completes a circuit through contacts 62. v

The operation'ot the relay 46 resulting from The means above describedfor starting and Y The 40 movable contact of the relay 46 is operable tothe momentary closing and opening 01' the load circuit l2, I3sequentially operates a predetermined number of time element relays 53,54, 55 and 56 through circuits which are completed through contacts 45and 52 of the relay. These relays are the type having adjustable timedelay opening characteristics. They are interconnected with one anotherthrough circuits completed by contacts which are closed in the open orclosed positions of the relays and through contacts closed by theoperation of the load circuit relay 46.

The operating circuit of relay 53 is completed through the followingcircuit: from one terminal 42 of the source of supply 42, 43 throughconductor 44, contacts 45 of relay 46, conductor 51, contacts 58 closedwhen relay 54 is in its open position, conductor 58, operating coil 68of relay 53 and conductor 48 to the other terminal 43 of the source ofsupply 42, 43. An operating circuit for relay 54 is completed asfollows: from conductor 42 of the source of supply 42, 43 throughconductor 44, contacts 52 of relay 46, conductor 6|, contacts 62 whichare closed when relay 53 is closed, conductors 63 and 64, the operatingcoil 65 of relay 54 and conductor 48 to the other conductor 43 of thesource of supply 42, 43. The operating circuit for relay 55 is completedas follows: from one conductor 42 of the source of supply 42, 43 throughconductor 44, contacts 45 of relay 46, conductor 51, contacts 66 closedwhen relay 54 is closed, conductors 61, 68 and 68 through the operatingcoil 18 of relay 55 and conductor 48 to the other conductor 43 of thesource of supply 42, 43. The operating circuit of the fourth relay 56 iscompleted through the following circuit: from one conductor 42 of thesource of supply 42, 43, through conductor 44, contacts 52 of relay 46,conductor 6|, contacts 62 closed when relay 53 is closed, conductor 63,contacts 1| which are closed when relay 55 is closed, conductor 12,operatingcoil 13 of relay 56, and conductor 48 to the other conductor 43of the source of supply 42, 43. When closed relay 56 is also energizedthrough the following circuit: from one conductor 42 of the source ofsupply 42, 43 through conductor 44, contacts 45, of relay 46, conductor51, contacts 66 of relay 54, closed when relay 54 is closed, conductors61, 68, contacts 14 which are closed when relay 56 is closed, holdingcoil 15 of relay 56 and conductor 48 to the other conductor 43 of thesource ofsupply 42, 43,

The relays 53, 54, 55 and 56 under the control of load circuit relay 46operate a voltage varying means for the generator l8 which means isdriven by a motor 16 energized through either of two control circuitswhich are selected by the relay 56 in its open or closed positions.circuit is connected across the source 42, 43 through conductors 44,contacts 45 of relay 46, conductor 51, contacts 66 of relay-54 andconductor 61, contacts 11' closed when relay 53 is open, conductor 18,contacts 18 closed when relay 56 is open, conductor 88, limit switch 8|,conductor 82, motor 16 and conductor 83. The other control circuit iscompleted asfollows: through conductor 44, contacts 45 of relay 46,conductor 51, contacts 66 of relay 54,conductor61,contacts 11 of relay53, conductor 18,contacts 84 closed when relay.56 is closed, conductor85, limit switch 86,conductor'85',motor 16,- and conductor 83.

The operation of the motor 16 gradually varies the voltage of thegenerator |8 through the operation of a rheostat 81 and the operation ofa tap changing switch 88. The rheostat 81 controls One control c theenergization of a separately excited field E8 of the generator and thetap changing switch 88 controls the number of turns of its series field88 which is connected in the load circuit |2, |3. When the motor 16isenergized through one of the control circuits above described itrotates in one direction gradually increasing the excitation of thegenerator l8, and when it is energized through the other control circuitdescribed above it rotates in the opposite direction graduallydecreasing the energization of the generator l8. Themotor 16 ismechanically connected to the arm 8| of the rheostat 81 and to theoperating element 82 of a Geneva movement, the other element 93 of whichis attached to a rotating arm 84 movable over contacts 85 to which theseveral turns of the field 88 are respectively connected. Conductor I3of the load circuit is electrically connected to arm 84 which alsooperates two limit switches 8| and 86.

With the parts in their position illustrated in the drawing, thegenerator I8 is fully excited, all of the turns of the series fieldbeing connected in the load circuit l2, l3 and the resistance ofrheostat 81 being reduced to a minimum. Rotation of the motor 16 in aclockwise direction will decrease the excitation of the generator |8 byfirst decreasing the strength of its field 88 by gradually inserting theresistance of the rheostat 81 in circuit therewith and when the fullresistance of the rheostat 81 has been inserted in circuit with thefield 88 by operating the tap changing switch 88 to decrease the numberof turns of the series field 88 connected in the load circuit. Rotationof the motor 16in the opposite direction will increase the excitation ofthe generator l8 in a reverse sequence. The time of operation of themotor 16 depends upon the timedifferential between the operation of therelays 53 and 54 and the direction of rotation of the motor 16 dependson which of its two control circuits is energized which in turn isdetermined by the position of the relay 56.

As has been pointed out above, the generator illustrated in the drawingis provided with a separately excited field 88 and a series field 88.The separately excited field 88 is connected across a source of supply42, 43 and the field winding 88 is, as has been pointed out above,connected in series relation with the load circuit 2, Generators havingdifierent field arrangements may be employed without departing from myinvention. When a source of separate excitation 43 is not readilyavailable I prefer to employ a generator having the construction andcircuit connections illustrated in Patent No. 1,340,004, Sven R.Bergman, granted May 11, 1920, in which case the circuit 42, 43 may beconnected across the constant potential brushes of the generator and thesystem will consequently be self-contained.

As has been pointed out above, the system disclosed is a welding systemand its operation will consequently be described in connection with awelding operation. The system is intended for use in those applicationswhere the welding operator finds it necessary to perform a weldingoperation at a point remote from the welding set, and is intended toenable him to control at the point of welding the voltage adjustment ofthe int ber of times. At the same time the arrangement is such thatunexpected arc interruptions during welding, or repeated attempts tostrike a welding arc will in no way disturb the voltage adjustment whenthe welding set IO, N has been shut down due to the operator's failureto perform a welding operation for a predetermined .length of time.

To start the welding operation the operator touches the electrode M tothe work i5. This completes a short circuit connection through thesecondary of the transformer I6 which as has been pointed out comprisesthe load circuit l2, I3. The closure of the secondary circuit of thetransformer l6 increases the flow of current in its primary circuit andcauses the relay 22 to operate. The operation of relay 22 closescontacts 29 which establishes the operating circuit of the coil 21 ofswitch 25 as follows. From one conductor of the source of supply l8through conductor 30, stop switch 3|, conductors 32 and 33, contacts 29of relay 22, conductors 34 and 35, contacts 36 of relay 31, conductor38, operating coil 21 of switch 25, and one of the conductors 26 to thesource of supply l8. After the switch 25 is closed it completes amaintaining circuit through contacts 40 as follows: from one conductorof the source of supply l8 through conductor 3!), switch 3|, conductors32 and 33, contacts 40 of switch 25, conductor 35, contacts 36 of relay31, conductor 38, operating coil 21 of switch 25, one of the conductors26 to another conductor of the source of supply l8. The connection ofthe motor I to the source of supply |8 causes the same to operate thegenerator H] which soon builds up its voltage. The welding system is nowoperating so that the welding operatorcan initiate his weldingoperation. If, however, the operator fails to perform a weldingoperation after a predetermined length of time which depends upon theadjustment of relay 31 the welding set will shut down. Thus, as soon asthe voltage of the generator [0 has built up to a value greater than thearcing voltage of the welding arc the relay 46 completes a circuitthrough contacts 45 which energizes the operating coil 4| of the relay31. This circuit is completed as follows:-From conductor 42 of thesource of supply 42, 43, through conductor 44, contacts 45 of relay 46,conductor 41, operating coil 4| of relay 31, and conductor 48 to theother conductor 43 of the source of supply. The energization of therelay 31 for a predetermined length of time causes the separation of thecontacts 36 of this relay which'interrupts the circuit through operatingcoil 21 of switch 25, and this switch opens thus disconnecting the motorII from the source of supply It. I

If upon initiating a welding operation the operator decides that thevoltage of the welding By twice touching the electrode= lays 53, 54, 55and 56, through the circuits above traced. Relay 53 is energized throughcontacts 45 of relay 46 and relay 54 is energized through contacts 52 ofrelay 46 and contacts 62 of relay 53. Thereafter the closure of contacts45 of'relay 46 energizes relay 55 through contacts 66 of relay 54 andthe'second closure of contacts 52 of relay 46 energizes relay 56 throughcontacts 62 of relay 53 and contacts 1| of relay 55. Thereafter thesecond closure of contacts 45 completes through contacts 66 of relay 54and contacts 14 of relay 56 the holding circuit of this relay. It isbecause of the time delay opening characteristics of these relays thatsuch circuit connections are possible. The closure of relay 56 completesone of the control circuits of motor 16 as follows: from conductor 42 ofthe source of supply 42, 43, through conductor 44, contacts 45 of relay46.,

conductor 51, contacts 66 of relay 54, conductor 83, to conductor 43.The motor 16 will then' operate to insert a portion or all of theresistance of the rh'eostat 81 and after all of the resistance of therheostat has been inserted to operate the Geneva movement 92, 93 to cutout a portion of the series winding 90 through the agency of the tapchanging switch 88. This change is gradual depending upon the speed ofoperation of the motor 16 and continues for a period of time determinedby the time differential of relays 53 and 54. Thus, if relay 53 isadjusted to release after one second, and relay 54 to release after twoseconds, the motor 16 will be energized for one second. At the end ofthe two seconds period of time relay 54 will release opening the abovetraced control circuitat contacts 66. The opening of these contacts willalso deenergize the holding coil 15 of the relay 56 allowing it torelease to its open position.

If after having thus adjusted the voltage of the generator the operatordesires to raise the voltage, this can be accomplished by momentarilyclosing the load circuit, i2, l3 by momentarily touching the electrodel4 to the work and thereafter separating it therefrom without strikingan are. This procedure will cause the relay 46 to operate in such manneras to complete the energizing circuits of relays 53 and 54which in turnwill complete the other control circuit of the control motor 16 throughthe following circuit: from conductor 42 of the source 42, 43, throughconductor 44, contacts 45 of relay 46, conductor 51, contacts 66 ofrelay 54, conductor 61, contacts 11 of relay 53, conductor 18, contacts19 of relay 56, conductor 80, limit switch 8|, conductor 82,

control motor 16 and conductor 83 to the other is one second. Thus,after the operator has touched his electrode momentarily to the workonce or twice and thereafter holds it away from the work withoutstriking a welding arc, the voltage varying means of the generator I0 isbrought into operation for one second. If the operator does not withdrawhis electrode from the work and wait for this predetermined length oftime nothing will occur. Thus, in those cases where the operatorhas,.experienced anunexpected in terruption or the welding arc andimmediately restrikes the arc and in those cases where one or moreattempts are made to strike the arc terminating in the establishment ofan arc the relay 6 will'close contacts 52 and open contacts 45 andremain in this position during the welding operation. The opening ofcontacts 45 will deenergize relay 53, and the opening of this relay willdeenergize relay 54 so that all of the time element relays will be intheir open positions a predetermined time after the welding arc has beenestablished.

It will thus be seen that I provide a system in which the voltage of thewelding set may be adjusted by the operator at his point of weldingsimply by touching his electrode a predetermined number of times to thework. Also, as has been pointed out above, the operator can start theset by touching his electrode to the work and, if weldingoperations aresuspendedfor anyv length of time after the welding set is in operation,it will shut down .of its own accord.

In the arrangement shown in Fig. l a voltage responsive relay 46has'been employed. Under some conditions of use it will be founddesirable to use a current responsive relay 96, Fig. 2, whose operatingcoil 91 is connected across a shunt 88 connected in the load circuit l2,l3. The control circuits through the contacts 45 and 52 of this relaywill be as illustrated above with the exception that the controlcircuits 51 and lil are reversed in view of the fact that in a currentresponsive system the relay 96 will be energized when the electrode Hengages the work l5 and will be deenergized when the electrode isseparated from the work without striking an arc.

The system above described may be variously modified without departingfrom my invention. It is, of course, apparent that various types of timeelement relays may be used, depending on the timing characteristicsrequired. Thus in practice relay 3'! may be of the motor or clock typeinorder to secure appreciable time delays. It is also apparent thatinstead of using relays 53, 54, 55 and 56 having time delay opening,relays having a time delay closing may be employed by suitably alteringthe control circuits as well as the time of operation of the relays toperform the functions above described. Various types of generators maybe employed and characteristics other than the voltage thereof may becontrolled by a system embodying the features of my invention. Thus,while I have described and illustrated two embodiments of my invention,it is to-be understood that other embodiments may be made withoutdeparting from the spirit and scope of my invention as defined in theclaims annexed to and forming a part of this specification.

What I claim-as new and desire-to secure by Letters Patent of the UnitedStates, is:

1. A power system comprising a generator, a load circuit connected tosaid generator, means for gradually varying a characteristic of saidgenerator, and time element means responsive to a predetermined numberof momentary closures of said, load circuit for energizing saidgenerator characteristic varying means for a predetermined length oftime, said time element means including a plurality of interconnectedtime element relays and said predetermined length of time depending onthe time differential of the operation of two of said time elementrelays.

2. A power system comprising a generator, 9.

7 load circuit connected to said generator, means for varying thevoltage of said generator, means including relays having different timedelay op-- erating characteristics for operating said voltage varyingmeans a predetermined length of time corresponding to a timedifferential of said relays, and means responsive to predeterminednumbers of momentary closures of said load circult for selectivelyenergizing said voltage varying means to raise or lower the voltage ofsaid generator.

3. A power system comprising a generator, a load circuit connected tosaid generator, means for varying the voltage of said generator, meansincluding relays having different time delay operating characteristicsfor operating said voltage varying means a predetermined lengthm of timecorresponding to a time differential of such relays, and meansresponsive to predetermined numbers of momentary closures of said loadcircuit for selectively energizing said voltage varying means to raiseor lower the voltage of said generator, said 'means being effective onlyif said load circuit is maintained open for a predetermined period oftime.

4. A power system comprising a generator, a load circuit connected tosaid generator, means for gradually varying the voltage of saidgenerator, time element means responsive to a predetermined number ofmomentary closures of said load circuit for energizing said voltagevarying means in one sense for a predetermined length of time, and timeelement means responsive to a differential number of momentary closuresof said load circuit for energizing said voltage varying means in theopposite sense for a predetermined length of time, said time elementmeans including a plurality of interconnected time element relays andsaid predetermined length of time depending on the time differential ofthe operation of two of said time element relays.

5. A power system comprising a. generator, 8. load circuit connected tosaid generator, a relay connected to said load circuit and operable totwo positions one of which corresponds to open circuit conditions onsaid load circuit and the other of which corresponds to closed circuitconditions on said load circuit, means for varying the' voltage on saidgenerator, four interconnected relays having time delay openingcharacteristics the operating circuit of the first of said time elementrelays being completed through contacts closed when the second of saidrelays is open and said load circuit relay is in its positioncorresponding to open circuit conditions on said load circuit, theoperating circuit of the second of said time element relays beingcompleted through contacts closed whenthe first of said time elementrelays is closed and said load circuit relay is in its positioncorresponding to closed circuit conditions on said loadcircuit, theoperating circuit of the third of said time element relays beingcompleted through contacts closed when the second of said time elementrelays is closed and said load circuit relay is in its positioncorresponding to open circuit conditions on said load circuit, and theoperating circuit of the fourth of the said time element relays beingcompleted through contacts closed when the first and third of said timeelement relays are closed and said load circuit relay is in its positioncorresponding to closed circuit conditions on said load circuit, meansincluding the voltage of said generator, said circuits being clementrelays being completed through contacts closed when the second of saidrelays is open and said load circuit relayis in its positioncorresponding to open circuit conditions on said load circuit, theoperating circuit of the second of said time element relays beingcompleted through contacts closed when the first of said time elementrelays is closed and said load circuit relay is in its positioncorresponding to closed circuit conditions on said load circuit, theoperating circuit of the third of said time element relays beingcompleted through contacts closed when the second of said time elementrelays is closed and said load circuit relay is in its positioncorresponding to open'circ-uit conditions on said load circuit, and theoperating circuit of the fourth of the time element relays beingcompleted through contacts closed when the first and third of said timeelement relays are closed and said load circuit relay is in its positioncorresponding to closed circuit conditions on said load circuit, and theholding circuit of the fourth of said time element relays beingcompleted through contacts closed when said relay is closed, said secondrelay is closed,

and said load circuit relay is in its position corresponding to opencircuit conditions on said load circuit, means including a circuitcompleted when said fourth time element relay is 'in its closed positionfor varying the voltage of said generator, and means including a circuitcompleted when said fourth time element relay is in its open positionfor oppositely varying the voltage of said generator, said circuitsbeing completed through contacts closed when said first mentioned timeelement relay is open and said second time element is closed.

7. A power system comprising a source of supply, a load circuitconnected to said source of supply and means including a plurality'ofinterconnected successively operated time element relays for varying acharacteristic of said source in response to momentary closures of saidload circuit, the extent of successive operation of said relays beingresponsive to and differing in accordance with the number of times saidload circuit is momentarily closed,

8. A power system comprising a source of supply, a load circuitconnected to said source 0! supply and means including a plurality ofinterconnected successively operated time element relays for varying acharacteristic of said source in one sense in response toa predeterminedextent of successive operation of said relays and in an opposite sensein response to a different predetermined extent of successive operation01' said relays, the extent of successive operation of said relays beingresponsive to and differing in accordance with corresponding numbers ofmomentary closures of said load circuit.

' BENJAMIN w. JONES.

